I am not sure, mind you, CS, that no traditional songs will ever more be writ [in the sense you have just used this phrase]. Traditional artefacts still certainly appear by oral tradition ~ urban myths; jokes: & some songs also, in fact ~ football chants, children's songs... All surely part of the anonymous oral tradition however you define it. To what extent, if any, serious, adult more extensive songs are appearing or will ever again appear is perhaps less clear: but I don't think the possibility can be entirely written off.